TP53 and glioblastoma: To explore whether Smad1 regulates p53 activity in GBM cells, we further analyzed the occupancy of p53 on the promoters of Smad1 depletion‐induced genes using chromatin immunoprecipitation sequencing (ChIP‐seq) data published previously (GSE46641).[24] Of the 2079 genes containing p53 binding peaks, the distance between the p53‐binding region (p53BR) and gene transcription starting site (TSS) among 196 genes was less than 20 kb.